Year	Percent
1991	60.976
1992	58.31
1993	54.404
1994	54.28
1995	54.056
1996	53.384
1997	52.883
1998	53.135
1999	52.347
2000	53.38
2001	52.971
2002	52.631
2003	52.26
2004	51.789
2005	65.114
2006	63.692
2007	62.782
2008	61.628
2009	59.648
2010	60.243
2011	60.407
2012	60.161
2013	59.457
2014	58.895
2015	58.97
2016	59.378
2017	59.465
2018	59.43
2019	59.382
2020	59.325
2021	59.267
2022	59.209